When should a parent lose the right to raise a child? FRONTLINE goes behind the scenes of one state's child welfare system in a two-part series to probe one of the most drastic and unchecked governmental powers. What is the proper balance between saving a child and destroying a family? In a two-part series, "Failure to Protect," FRONTLINE probes the complexities and difficulties in trying to answer that question through a remarkable behind-the-scenes look at Maine's child protective services. Part One, "The Taking of Logan Marr," tells the tragic story of a young girl who was killed while in state custody. On Jan. 31, 2001, 5-year-old Logan Marr was found dead in her foster mother's home in Chelsea, Maine. The foster mother, Sally Schofield, was a highly respected former caseworker for Maine's Department of Human Services (DHS). She would later be convicted of manslaughter after police determined that Logan had died from asphyxiation in Sally's basement, where she had been bound with duct tape and strapped into a high chair. The death of Logan Marr prompted public outrage. Why did the state remove Logan from her mother, Christy Marr, when there was no evidence of physical or sexual abuse? Did the DHS move too quickly to terminate Christy's parental rights? And did it fail to heed warning signs that Logan was in danger? Through extensive interviews with the parties involved -- including an exclusive interview with Sally Schofield -- the one-hour documentary investigates the events that led to Logan's death. It also tells the story of the two women locked in a battle over Logan: Christy, who fought to prove to DHS that she should have her daughter back, and Sally, who remained determined to adopt Logan, even as she struggled to control the troubled child. Through their stories, "The Taking of Logan Marr" casts light on a system that is almost always cloaked in secrecy: state child protective services. "The termination of a parent's rights to their child is one of the most drastic decisions the state is called upon to make -- yet it does so with little or no public scrutiny," says Barak Goodman, who co-produced the documentary with his wife, Rachel Dretzin, and Muriel Soenens. "The system is almost always shrouded by confidentiality agreements and privacy laws." While senior DHS officials in Maine declined to be interviewed about the Logan Marr case, they did make an unprecedented offer -- they would allow FRONTLINE's producers to film their normally confidential child protective system from the inside for more than four months. The result is Part Two of the "Failure to Protect" series: a one-hour documentary called "The Caseworker Files." "The Caseworker Files" follows a small set of caseworkers as they interact with families and each other and have to confront some excruciating dilemmas and choices: Who decides when a child should be removed from her parents? When should parents lose the right to raise their own child? And how much damage might we do to children in the name of helping them? "We found a system where caseworkers, many of whom are relatively inexperienced, struggle under heavy caseloads as an ever-increasing number of children are placed in foster care," says Goodman. "We also found angry and resentful parents who feel that their children are being taken away from them before they've been given a fair chance to improve things." "The Caseworker Files" reveals a child welfare system that in recent years has undergone a major philosophical shift. Whereas once the emphasis was placed on trying to eventually reunite children with their biological parents -- a policy that often left children languishing in foster care for years -- state and federal guidelines now favor fast-tracking adoption of children in foster care, a move that requires the state to terminate the biological parents' rights.